The present invention relates to an image processing method and apparatus, recording medium and imaging apparatus, and particularly to an image processing method and apparatus for adjusting pixel values constituting an image, a medium recorded with a program for causing a computer to implement such an image processing function, and an imaging apparatus comprising such an image processing apparatus.
In a magnetic resonance imaging (MRI) apparatus, an object to be imaged is carried into an internal space of a magnet system, i.e., a space in which a static magnetic field is generated; gradient magnetic fields and a high frequency magnetic field is applied to cause spins within the object to generate magnetic resonance signals; and a tomographic image is produced based on the received signals.
The effect of the gradient magnetic fields and high frequency magnetic field on the spins is different between the spins that move inside the body such as those in blood flow, and the spins that do not move such as those in a tissue. By using this difference, an image of the spins that move inside the body, i.e., for example, a blood flow image, may be captured.
In capturing the blood flow image, a time-of-flight (TOF) technique, phase contrast (PC) technique or the like is employed.
A blood flow projection image in a three-dimensional region is obtained by using one of these techniques to capture multi-slice blood flow tomographic images with respect to the three-dimensional region, and performing maximum intensity projection (MIP) on the multi-slice blood flow tomographic images in the slice thickness direction.
When a projection image of blood flow is obtained as described above, faint blood flow may not be projected because it is obscured by noise. Moreover, when the average signal intensity of an image is different among slices, a blood flow image in an image with a small average signal intensity cannot be projected because it is obscured by noise in an image with a large average signal intensity.